Why does Earth's tilt produce summers and winters?

One explanation I have never understood is that we have Summers and
Winters because Earth is tilted.

On a hot Summer day, I cannot cool myself by "tilting" my body in any
direction. My body still gets the heat that falls on it, no matter the
tilt. Otherwise people would have discovered this trick long ago and we
wouldn't need fans or air-conditioning.

So...if you understand why tilt at an angle works for Earth, please do
explain in simple English.

On Thu, 02 Nov 2006 07:06:24 GMT, AlexZ <[Only registered users see links. ]> wrote:


One half of the globe is always pointed towards the sun, so you are
right that tilting it cannot change the amount of "heat falling on
it". Now imagine the globe spinning so that every part of the globe
goes in and out of the light to produce day and night. Next, tilt (in
your mind, or use an orange and a lamp if you want) the top of the
globe away from the light. You will notice that the "top", ie the
point around which the globe is spinning, never gets any light at all,
whereas the "bottom" is in the light all the time. In Earth terms,
that means the North Pole is in total darkness (winter) and the South
Pole has summer. Between those extremes, the "season" varies from
summer to winter depending on where "you" are on the globe at the
time. If you then (without altering the tilt) move the globe (or
orange) to the other side of the lamp, you will see that it is the
North Pole that is in the light (summer) and the South Pole has
winter. The real Earth does the same in travelling round the sun once
per year, and so the seasons change.

AlexZ wrote:


Try using solar panels instead of your body!

Ben Newsam wrote:


I need a clarification as well. Is the moon's gravity a major facotr in
the earth's tilt? In the absence of the moon will the tilt be
different? Can some one clarify? Thanks

Dear Alexz:

"AlexZ" <[Only registered users see links. ]> wrote in message
news:[Only registered users see links. ]...

You can get yourself cool*er*, by keeping the shadow of your head
where your feet are. If you were to lay out flat, the Sun would
make you warmer still.


You have two effects:
1) The area doesn't change, but the incident light does change
with angle. More tilt, and any particular area gets less
delivered power.

Your "body" analogy ignores that if one small area is tilted
away, another is tilted towards.

2) During a full day, any particular latitude (how far N / S
from the equator you are) will have a different length of day or
length of night, depending on how the Earth's axis is oriented
with respect to the Sun.

[Only registered users see links. ]
[Only registered users see links. ]

David A. Smith

Dear tripurantaka:

<[Only registered users see links. ]> wrote in message
news:1162472822.838973.307050@k70g2000cwa.googlegr oups.com...
....

[Only registered users see links. ]

David A. Smith

N:dlzc D:aol T:com (dlzc) wrote:

[Only registered users see links. ] is pretty out of data
as is says...

"Without the Moon, there might not be any seasons, or the seasons
might be very different ones. It is believed that the Moon is an
interloper from a more distant spot in the solar system which was
captured by the Earth billions of years ago. This capture would
have caused the rotation axis of the Earth to be seriously shifted
to where it is now. The Earth may have started off with a rotation
axis pointing almost perpendicular to the plane of the solar
system, rather than canted at 23.5 degrees as it is now. Without
this tilt, the rays from the Sun would always strike the Earth's
surface at a fixed angle every day of the year. At the Earth's
equator, the Sun's rays would always be perpendicular to the ground
all year long. At a latitude of 45 degrees, they would strike the
ground at 45 degrees every day, and at the North and South Poles,
the Sun would never make it above the horizon".

The scientific evidence strongly suggests that the moon was formed
as the result of a major collision with the young earth. The impact
certainly also contributed to the degree of tilt in the earth's axis
of rotation.

Dear Sam Wormley:

Sam Wormley wrote:
....

Thanks, Sam. I guess I've got to a little better quality control on my
links.

David A. Smith

AlexZ <[Only registered users see links. ]> wrote:


I don't have an answer but a similar question: Why are the poles so
much colder than the equator?

I imagine that the Earth's size is much smaller than Earth-Sun
distance, so the poles and the equator are more or less equidistant
from the Sun...

Moreover, one of the poles is always facing the Sun and therefore does
receives sunlight. Then, why is this Sun-facing pole colder than the
Equator?

Ajanta <[Only registered users see links. ]> writes:






Possibly because at the poles, the sun can never rise above the horizon
farther than 23.5°, while at the equator, it's *always* straight overhead in a
belt that extends the same 23.5° north and south of the equator. (In other
words, less atmosphere to have to heat up in the tropics, compared to a bit
more at the poles.)

--
Patrick "The Chief Instigator" Humphrey ([Only registered users see links. ]) Houston, Texas
chiefinstigator.us.tt/aeros.php (TCI's 2006-07 Houston Aeros)
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